Indicia reading terminal including frame processing

ABSTRACT

There is described an indicia reading terminal that can be operative to process a frame of image data for attempting to decode a decodable indicia. A frame can be a frame that is among a succession of frames for subjecting to processing subsequent to and during a time a trigger signal is active. Such a succession of frames can include zero or more binned frames, zero or more unbinned frames, zero or more windowed frames, and zero or more unwindowed full frames. An indicia reading terminal can also include a variable focus imaging lens. Control of the variable focus imaging lens can be provided so that during an exposure period for a binned frame the variable focus imaging lens is set to a short range focus setting and further so that during an exposure period for a windowed frame the variable focus imaging lens is set to a long range focus setting.

FIELD OF THE INVENTION

The present invention relates to registers in general and in particularto an optical based register.

BACKGROUND OF THE INVENTION

Indicia reading terminals are available in multiple varieties. The wellknown gun style reader as commonly seen at retail store checkoutcounters is typically available in a form devoid of a keyboard anddisplay. Enhanced functioning indicia reading terminals having keyboardsdisplays and advanced networking communication capabilities are alsoavailable. Typically, indicia reading terminals have triggers foractivating decoding attempts.

Manufacturers of indicia reading terminals have incorporated imagesensor arrays having increased resolution (as measured in terms ofnumbers of pixels) into their indicia reading terminals. However,performance and cost disadvantages are introduced as a number of pixelsof an image sensor array is increased. As pixel size becomes smaller, ayielded signal to noise ratio (SNR) becomes lower potentially impactingdecode performance as well as hand motion tolerance. Also, as a numberof pixels increases, memory bandwidth overhead increases.

SUMMARY OF THE INVENTION

There is described an indicia reading terminal that can be operative toprocess a frame of image data for attempting to decode a decodableindicia. A frame can be a frame that is among a succession of frames forsubjecting to processing subsequent to and during a time a triggersignal is active. Such a succession of frames can include zero or morebinned frames, zero or more unbinned frames, zero or more windowedframes, and zero or more unwindowed full frames. An indicia readingterminal can also include a variable focus imaging lens. Control of thevariable focus imaging lens can be provided so that during an exposureperiod for a binned frame the variable focus imaging lens is set to ashort range focus setting and further so that during an exposure periodfor a windowed frame the variable focus imaging lens is set to a longrange focus setting.

BRIEF DESCRIPTION OF THE DRAWINGS

The features described herein can be better understood with reference tothe drawings described below. The drawings are not necessarily to scale,emphasis instead generally being placed upon illustrating the principlesof the invention. In the drawings, like numerals are used to indicatelike parts throughout the various views.

FIG. 1 is a functional block diagram illustrating an embodiment of anindicia reading terminal;

FIG. 2 is a diagram illustrating field of view size of an exemplaryindicia reading terminal wherein a field of view encompasses a largerarea of a target substrate at longer range terminal to target distances,and where a pixel/mil. (or pixel/inch) resolution of a representation ofa same sized decodable indicia is lower at longer distances;

FIG. 3 is a block diagram illustrating an exemplary hardware platformfor executing a method described herein;

FIG. 4 is a diagram illustrating operations that can be performed by abinning module of an indicia reading terminal;

FIG. 5 is a diagram illustrating operations that can be performed by awindowing module of an indicia reading terminal;

FIG. 6 is an exploded perspective view of an imaging module carrying asubset of circuits as shown in FIG. 3;

FIG. 7 is an assembled perspective view of the imaging module as shownin FIG. 6;

FIG. 8 is a perspective view of a hand held indicia reading terminalincorporating an imaging module as shown in FIGS. 6 and 7;

FIG. 9 is a timing diagram illustrating a timing of various operationsthat can be carried out by an indicia reading terminal.

DETAILED DESCRIPTION OF THE INVENTION

A functional block diagram including an embodiment of indicia readingterminal 1000 is shown in FIG. 1. Terminal 1000 can include one or moreof a binning module 10 for binning a frame of image data and forproviding a binned frame of image data, a windowing module 20 forproviding a windowed frame of image data, a focus control module 30 forsetting a focus of a variable focus imaging lens of terminal 1000, andan indicia decoding module 40 for attempting to decode a frame of imagedata.

As shown in FIG. 2, a surface area encompassed by a field of view of anindicia reading terminal 1000 expands at longer reading distances. Thusat a relatively shorter terminal to target distance, d₁, a decodableindicia 15 of a given physical size area will consume a larger portionof a field of view 140 as compared to field of view 140 at a relativelylonger terminal to target distance, d₂. In one embodiment, terminal 1000is operative to process one or more of binned frames of image data andto capture windowed frames of image data. Binned frames are particularlyadvantageous for use in decoding of decodable indicia at shorter rangeterminal to target distances. At relatively shorter terminal to targetdistances, pixel resolution is less significant a factor in determiningdecoding speed or likelihood of decoding; accordingly, binning allowsfor an increased signal to noise ratio, while allowing frame capture ata resolution sufficient for purposes of decoding. Also, as binned framescomprise a smaller number of pixel positions than unbinned framesrepresenting the same area in physical space, binned frames reducememory bandwidth overhead. Use of windowed frames is particularly usefulfor decoding of frames of image data at longer terminal to targetdistances. Windowed frames can be captured more rapidly than standardsize frames. As frames captured at longer terminal to target distancescan be expected to have a large amount of extraneous image data notrepresenting a decodable indicia outside the area of the windowed frame,windowing at longer terminal to target distances can reduce imagecapture time without reducing a likelihood of a successful decode. Also,as windowed frames include fewer pixel values than full frames, windowedframes reduce memory bandwidth overhead.

An exemplary hardware platform for carrying out the described method isshown and described with reference to the block diagram of FIG. 3.Indicia reading terminal 1000 can include an image sensor 1032comprising a multiple pixel image sensor array 1033 having pixelsarranged in rows and columns of pixels, associated column circuitry 1034and row circuitry 1035. Associated with the image sensor 1032 can beamplifier circuitry 1036, and an analog to digital converter 1037 whichconverts image information in the form of analog signals read out ofimage sensor array 1033 into image information in the form of digitalsignals. Image sensor 1032 can also have an associated timing andcontrol circuit 1038 for use in controlling e.g., the exposure period ofimage sensor 1032, gain applied to the amplifier circuitry 1036. Thenoted circuit components 1032, 1036, 1037, and 1038 can be packaged intoa common image sensor integrated circuit 1040. In one example, imagesensor integrated circuit 1040 can be provided by an MT9V022 imagesensor integrated circuit available from Micron Technology, Inc. Inanother example, image sensor integrated circuit 1040 can be provided bya Micron MT9PO31 image sensor having a 2592×1944 pixel image sensorarray. In one embodiment, image sensor integrated circuit 1040 canincorporate a Bayer pattern filter. In such an embodiment, CPU 1060prior to subjecting a frame to further processing can interpolate pixelvalues intermediate of green pixel values for development of amonochrome frame of image data. Also, for development of a monochromeframe of image data, binning module 10 can be activated for processingcolor image information of a color frame of image data.

In the course of operation of terminal 1000 image signals can be readout of image sensor 1032, converted and stored into a system memory suchas RAM 1080. Image data stored in RAM 1080 can be in the form ofmultibit pixel values, with each multibit pixel value representing lightincident on a pixel of image sensor array 1033. A memory 1085 ofterminal 1000 can include RAM 1080, a nonvolatile memory such as EPROM1082 and a storage memory device 1084 such as may be provided by a flashmemory or a hard drive memory. In one embodiment, terminal 1000 caninclude CPU 1060 which can be adapted to read out image data stored inmemory 1080 and subject such image data to various image processingalgorithms. Terminal 1000 can include a direct memory access unit (DMA)1070 for routing image information read out from image sensor 1032 thathas been subject to conversion and storage to RAM 1080. In anotherembodiment, terminal 1000 can employ a system bus providing for busarbitration mechanism (e.g., a PCI bus) thus eliminating the need for acentral DMA controller. Other embodiments of the system bus architectureand/or direct memory access components providing for efficient datatransfer between the image sensor 1032 and RAM 1080 can be provided.

Referring to further aspects of terminal 1000, terminal 1000 can includea variable focus imaging lens 1110 for use in focusing an image of adecodable indicia located within a field of view 140 on a substrate 50onto image sensor array 1033. Imaging light rays can be transmittedabout imaging axis 25. Variable focus imaging lens 1110 can be adaptedto be capable of multiple best focus distances and multiple focallengths. Variable focus imaging lens 1110 can be operative to provide anew best focus distance and/or focal length within a fraction of a frametime in response to an applied input control signal being applied to thevariable focus imaging lens 1110. Variable focus imaging lens 1110 canbe a deformable imaging lens, e.g., a deformable fluid lens or gel lens.Variable focus imaging lens 1110 can be a non-deformable fluid lens,e.g., an electrowetting liquid lens wherein the surface tension of oneor more volumes of lens liquid changes in response to a signal beingapplied to the lens, or a liquid crystal type lens wherein indices ofrefraction of one or more volumes of lens fluid change in response to asignal being applied to the lens.

Terminal 1000 can also include an illumination pattern light source bank1204 for use in generating an illumination pattern 60 substantiallycorresponding to a field of view 140 of terminal 1000 and an aimingpattern light source bank 1208 for use in generating an aiming pattern70 on substrate 50. Shaping optics 1205 and 1209 can be provided forshaping light from bank 1204 and bank 1208 into pattern 60 and intopattern 70 respectively. In use, terminal 1000 can be oriented by anoperator with respect to a substrate 50 bearing decodable indicia 15 insuch manner that aiming pattern 70 is projected on a decodable indicia15. In the example of FIG. 3, decodable indicia 15 is provided by a IDbar code symbol. Decodable indicia could also be provided by 2D bar codesymbols or optical character recognition (OCR) characters. Each ofillumination pattern light source bank 1204 and aiming pattern lightsource bank 1208 can include one or more light sources. Variable focusimaging lens 1110 can be controlled with use of focus control module 30and the illumination assembly comprising illumination pattern lightsource bank 1204 and aiming pattern light source bank 1208 can becontrolled with use of illumination assembly control module 1220. Focuscontrol module 30 can send signals to variable focus imaging lens 1110e.g., for changing a best focus distance and/or a focal length ofvariable focus imaging lens 1110. Illumination assembly control module1220 can send signals to illumination pattern light source bank 1204e.g., for changing a level of illumination output by illuminationpattern light source bank 1204. In one example, terminal 1000 can beadapted so that illumination assembly control module 1220 controls lightsource bank 1204 to have a relatively lower level of illumination outputwhen the best focus distance of imaging lens 1110 is set to a firstshorter best focus distance, and a relatively higher level ofillumination output when the best focus distance of imaging lens 1110 isset at a longer best focus distance. Such variable illumination settingscan be varied within a time that trigger signal 502 remains active. Thevariable illumination level settings can be synchronized to the certainlens settings set forth in connection with the various configurationsdescribed with reference to Table A herein.

Terminal 1000 can also include a number of peripheral devices such asdisplay 1304 for displaying such information as image frames capturedwith use of terminal 1000, keyboard 1404, pointing device 1406, andtrigger 1408 which may be used to make active a trigger signal 502 foractivating frame readout and/or certain decoding processes. Terminal1000 can be adapted so that activation of trigger 1408 activates triggersignal 502 and initiates a decode attempt.

Terminal 1000 can include various interface circuits for couplingvarious of the peripheral devices to system address/data bus (systembus) 1500, for communication with CPU 1060 also coupled to system bus1500. Terminal 1000 can include circuit 1026 for coupling image sensortiming and control circuit 1038 to system bus 1500, interface circuit1118 for coupling focus control module 30 to system bus 1500, interfacecircuit 1218 for coupling illumination control assembly 1220 to systembus 1500, interface circuit 1302 for coupling display 1304 to system bus1500, and interface circuit 1402 for coupling keyboard 1404, pointingdevice 1406, and trigger 1408 to system bus 1500.

In a further aspect, terminal 1000 can include one or more I/Ointerfaces 1604, 1608 for providing communication with external devices(e.g., a cash register server, a store server, an inventory facilityserver, a peer terminal 1000, a local area network base station, acellular base station). I/O interfaces 1604, 1608 can be interfaces ofany combination of known computer interfaces, e.g., Ethernet (IEEE802.3), USB, IEEE 802.11, Bluetooth, CDMA, GSM.

Aspects of binning module 10 and windowing module 20 in exemplaryembodiments are now described. Binning module 10 can be activated toprovide a binned frame of image data. An explanation of a binned frameis provided with reference to FIG. 4. In FIG. 4, grids are provided torepresent pixel positions. Each of an image sensor array 1033 and aframe of image information which can be stored for capture of a frame ofimage data can be regarded to comprise a plurality of pixel positions,each position having an associated picture element image informationvalue (sometimes referred to as a pixel value), expressed as a charge orvoltage prior to memory storage and expressed as a bit or multibit datavalue after storage. For providing of a binned frame, image informationvalues corresponding to multiple positionally adjacent pixel positionscan be (a) summed (b) averaged subject to another applied function. Abinned frame will have reduced resolution but higher brightness relativeto an unbinned frame (if the binned frame is provided by summing) or ahigher SNR relative to an unbinned frame (if the binned frame isprovided by averaging). Referring to FIG. 4, there is shown a pluralityof positionally adjacent pixel positions. For binning of a frame, imageinformation values of a 2×2 block of pixel positions e.g., a₀, a₁, a₂,a₃ can be summed. For example, the image information values of pixelpositions a₀, a₁, a₂, a₃ representing light incident on a 2×2 block offour positionally adjacent pixels can be summed to form an imageinformation value corresponding to position A (where position Arepresents the same areas of a physical space as formerly represented bya₀, a₁, a₂, a₃), the image information values of pixel positions b₀, b₁,b₂, b₃ representing light incident on a 2×2 block of four positionallyadjacent pixels can be summed to form an image information valuecorresponding to position B, and so on. In the described example,A=a₀+a₁+a₂+a₃; B=b₀+b₁+b₂+b₃; C=c₀+c₁+c₂+c₃; D=d₀+d₁+d₂+d₃;E=e₀+e₁+e₂+e₃; F=f₀+f₁+f₂+f₃; G=g₀+g₁+g₂+g₃; H=h₀+h₁+h₂+h₃;I=i₀+i₁+i₂+i₃. The binning process described can be repeated for allpixel positions of a frame. Binning module 10 in one embodiment caninclude analog binning circuit 1028 integrated into image sensorintegrated circuit 1040. Analog binning circuit 1028 can sum chargescorresponding to light incident on a set (e.g., a 2×2) block of pixelsof image sensor 1032. For readout of a binned frame, the binned framewill have resolution reduced relative to an unbinned frame and willinclude image information values for a set of pixel positions, whereeach pixel position corresponds to a 2×2 block of pixels of image sensorarray 1033, and each image information value will be a sum of charges ofthe pixels of each respective 2×2 block. Binning module 10 can also binframes in the digital domain. For binning in the digital domain, a frameof image data is stored into memory, e.g., memory 1080. Then imageinformation of the form of gray scale pixel values associated with pixelpositions corresponding to a block e.g., a 2×2 block of positions can besummed. Where binning module 10 bins frames in the digital domain, pixelpositions a₀, a₁, a₂, a₃, b₀, b₁ . . . are pixel positions of a frame ofimage data having gray scale pixel values, and pixel positions A, B, C,D, E, F, G, H, I are pixel positions of a resulting frame provided bybinning of a full resolution frame.

Also, for binning of a frame, image information of a 2×2 block of pixelpositions e.g., a₀, a₁, a₂, a₃ can be averaged. For example, the imageinformation value of pixel positions a₀, a₁, a₂, a₃ representing lightincident on a 2×2 block of four positionally adjacent pixels can beaveraged to form a image information value corresponding to position A(where position A represents the same areas of a physical space asformerly represented by a₀, a₁, a₂, a₃), the image information of pixelpositions b₀, b₁, b₂, b₃ representing light incident on a 2×2 block offour positionally adjacent pixels can be averaged to form an imageinformation value corresponding to position B, and so on. In thedescribed example, A=(a₀+a₁+a₂+a₃)/4; B=(b₀+b₁+b₂+b₃)/4;C=(c₀+c₁+c₂+c₃)/4; D=(d₀+d₁+d₂+d₃)/4; E=(e₀+e₁+e₂+e₃)/4;F=(f₀+f₁+f₂+f₃)/4; G=(g₀+g₁+g₂+g₃)/4; H=(h₀+h₁+h₂+h₃)/4;I=(i₀+i₁+i₂+i₃)/4. The binning process described can be repeated for allpixel positions of a frame. Binning module 10 in one embodiment caninclude analog binning circuit 1028 integrated into image sensorintegrated circuit 1040. Analog binning circuit 1028 can average chargescorresponding to light incident on a set (e.g., a 2×2) block of pixelsof image sensor 1032. For readout of a binned frame, the binned framewill have resolution reduced relative to an unbinned frame and willinclude image information values for a set of pixel positions, whereeach pixel position corresponds to a 2×2 block of pixels of image sensorarray 1033, and each image information value will be a sum of charges ofthe pixels of each respective 2×2 block. Binning module 10 can also binframes in the digital domain. For binning in the digital domain, a fullframe of image data is stored into memory, e.g., memory 1080. Then imageinformation in the form of gray scale pixel values associated with pixelpositions corresponding to a block e.g., a 2×2 block of positions can beaveraged. Where binning module 10 bins frames in the digital domain,pixel positions a₀, a₁, a₂, a₃, b₀, b₁ . . . are pixel positions of aframe of image data having gray scale pixel values, and pixel positionsA, B, C, D, E, F, G, H, I are pixel positions of a resulting frameprovided by binning of a full resolution frame.

A binned frame that is provided by averaging image informationassociated with a block of pixel positions features a reduced noiselevel and therefore a higher SNR than an unbinned frame. A higher SNRprovides a higher decode success rate. Also, a higher SNR permitssuccessful decodes in environments of lower illumination.

Binning module 10 can be advantageously activated to convert a colorframe to a monochrome frame. Where image sensor array 1033 includes aBayer pattern filter, a filter having the characteristics of Bayerpattern filter segment 1501 will be disposed over image sensor array1033. Without charges from the pixels being binned, an initial set ofimage information result of an image sensor array 1033 having a Bayerpattern filter will be color information including an image informationvalue from the one of green, red, or blue light incident on each pixelof the array. With binning executed by binning circuit 1028, eachresulting image information value will be a normalized monochrome imageinformation value. Unlike alternative color to monochrome conversionsystems binning module 10 when converting color image information tomonochrome does not discard image information. Binning module 10operative in the digital domain can also be activated for conversion ofa color frame to a monochrome frame. In another embodiment, binningmodule 10 can be capable of binning image information valuescorresponding to pixel positions of various block sizes. With referenceto FIG. 5, 2×2 block binning is described. Binning module 10 can also becapable of e.g., 4×4 binning. Binning module 10 can output a binnedframe based on image information corresponding to a block of pixelpositions using a function other than simple summing or averaging. Forexample, binning module 10 can provide color to gray level binning insuch manner as to utilize white balance co-efficiencies to reduce theMoiré pattern effect. For example, binning module 10 can provide binningusing the formula A=cr*a₀+cg*(a₁+a₂)/2+cb*a₃, where cr, cg, cb are whitebalance coefficients. Such coefficients can be obtained locally orglobally by e.g., white patch or gray world algorithm.

A binned frame as is described in connection with FIG. 4 can be capturedin less time than a full frame. The frame rate can increase when thesize of the binning block is increased. For example, where x is theframe rate for an unbinned frame, the expected frame rate for a binnedframe with a 2×2 binning block can be expected to be about 2× and theexpected frame rate for a binned frame with a 4×4 binning block can beexpected to be about 4×.

Regarding windowing module 20, windowing module 20 can provide awindowed frame of image data. Windowing module 20 can include windowingcircuit 1029 incorporated as part of image sensor integrated circuit1040. In response to commands received from CPU 1060 via circuit 1026and timing control circuit 1038, windowing circuit 1029 can selectivelyaddress for read out a subset of pixels of image sensor array 1033. Awindowed frame is further described with reference to FIG. 5. Imagesensor array 1033 can include a plurality of pixels arranged in aplurality of rows and columns of pixels as shown in FIG. 5. Terminal1000 can be operated to read out a full frame of image data from imagesensor array 1033. When reading out a full frame, terminal 1000 readsout image data corresponding to all or substantially all pixels of imagesensor array 1033 (e.g., from 80% to 100% of image sensory array 1033).When reading out a windowed frame of image data, terminal 1000 reads outimage information corresponding to a subset of pixels of image sensorarray 1033. In one example of a reading out of a windowed frame,terminal 1000 reads out image information corresponding to less than 80%of pixels of image sensor array 1033. In another example of a readingout of a windowed frame, terminal 1000 reads out image informationcorresponding to less than 50% of pixels of image sensor array 1033. Inanother example of a reading out of windowed frame, terminal 1000 readsout image information corresponding to less than ⅓ of the pixels ofimage sensor array 1033. In another example of a reading out of windowedframe, terminal 1000 reads out image information corresponding to lessthan 25% of pixels of image sensor array 1033. In another example of areading out of windowed frame, terminal 1000 reads out image datacorresponding to less than 10% of pixels of image sensor array 1033.

A particular example of a windowed frame read out is described withreference to FIG. 5. A windowed frame can comprise a continuous group ofpositionally adjacent pixel positions. A continuous group of pixels canbe provided where a group comprises each or essentially each pixelwithin a border defined by border pixels of a group. A group of pixelscan also have a group of pixels including border pixels defining aborder and skipped pixels within the border e.g., every other or everythird pixel with the border can be skipped. Group of pixels 1502 in theexample of FIG. 5 are pixels of image sensor array 1033 that areselectively addressed for read out of a windowed frame. The group ofpixels 1502 in the example of FIG. 5 is shown as including a continuousgroup of K×L, K>5, L>5 array of positionally adjacent pixels selectivelyaddressed from image sensor array 1033 having M×N pixels. A group ofpixels for subjecting to read out of a windowed frame could alsocomprise a continuous group of K−1, L>5 array of pixels where the groupof pixels are positionally adjacent such that each pixel position ispositionally adjacent to at least one other pixel position of the group.Windowing circuit 1029 can be controlled to dynamically vary a windowsize between successive frames. It will be seen that a windowed frame ata certain terminal to target distance and lens setting can representindicia within a defined area of a target substrate that is relativelysmaller than a defined area within which indicia would be represented bya frame representing each pixel of image sensor array 1033.

When a windowed frame of image information is read out and stored in amemory in the form of digital image data, an image representation isprovided having a number of pixel positions that is reduced relative tothat of an image representation corresponding to a full frame. Windowedframe of image data 1504 as illustrated in FIG. 5 has a number of pixelpositions corresponding to the number of pixels of group of pixels 1502selectively addressed for read out of a windowed frame. It has beenmentioned that image information read out from image sensor array 1033can be amplified by amplifier circuitry 1036 and then subject toconversion by analog to digital converter 1037 and then subject tostorage into RAM 1080. Stored image data stored into RAM 1080 can be inthe form of multibit pixel values. Windowed frame 1504 when stored inmemory 1085 where it can be addressed for processing by CPU 1060 cancomprise a plurality of pixel positions corresponding to the K×L arrayof pixels subject to selective addressing and selective read out, andeach pixel position can have associated therewith a multibit pixel valuerepresenting light incident at the pixel having the corresponding pixelposition of image sensor array 1033.

Windowed frame 1504 can be captured in less time than a full frame.Accordingly, when terminal 1000 switches from capture of a full frame toa windowed frame, a frame rate can increase and a frame time candecrease. As the number of pixel positions is reduced relative to thatof a full frame, a memory overhead bandwidth for storage of windowedframe 1504 can be reduced. Referring again to FIG. 5, it is seen thatwindowed frame 1504 can still be of sufficient size to include acomplete representation of decodable indicia 15 where group of pixels1502 is at a center of an image sensor array as shown in FIG. 5, whereindicia 15 is centered at a full frame field of view of terminal 1000and where indicia 15 is at a sufficient distance from terminal 1000.With aiming pattern generator comprising elements 1208, 1209 adapted toproject aiming pattern 70 at a horizontally extending centerline of afield of view 140, terminal 1000 can easily be located so that a portionof a field of view corresponding to group of pixels 1502 is centered onindicia 15.

Terminal 1000 can capture frames of image data at a rate known as aframe rate. A typical frame rate is 60 frames per second (FPS) whichtranslates to a frame time (frame period) of 16.6 ms. Another typicalframe rate is 30 frames per second (FPS) which translates to a frametime (frame period) of 33.3 ms per frame. A frame rate can increase (andframe time decrease) where a captured frame is a binned frame or awindowed frame.

Referring to FIGS. 6 and 7, an imaging module 300 for supportingcomponents of terminal 1000 can include image sensor integrated circuit1040 disposed on a printed circuit board 1802 together with illuminationpattern light source bank 1204 and aiming pattern light source bank 1208each shown as being provided by a single light source. Imaging module300 can also include containment 1806 for image sensor integratedcircuit 1040, and housing 1810 for housing imaging lens 1110. Imagingmodule 300 can also include optical plate 1814 having optics for shapinglight from bank 1204 and bank 1208 into predetermined patterns. Imagingmodule 300 can be disposed in a hand held housing 11, an example ofwhich is shown in FIG. 8. Disposed on hand held housing 11 can bedisplay 1304, trigger 1408, pointing device 1406, and keyboard 1404.

An example of an indicia reading terminal 1000 operating in accordancewith described processing is described with reference to the timingdiagram of FIG. 9. Referring to the timing diagram of FIG. 9, signal 502is a trigger signal. Terminal 1000 can be operative so that triggersignal 502 is made active responsively to trigger 1408 being actuatedand further so that trigger signal 502 remains active until the earlierof trigger 1408 being released or a predetermined number of a decodableindicia (e.g., 1) being successfully decoded and output. A decodedmessage corresponding to an encoded indicia that has been decoded can beoutput e.g., by storage of the message into a non-volatile memory, e.g.,memory 1084 and/or display of the decoded message on display 1304 and/ortransmitting the decoded message to an external CPU-equipped terminale.g., a locally networked personal computer or a remote server. Exposurecontrol signal 510 can be always active or else as in the embodimentshown in FIG. 9, terminal 1000 can be operative so that exposure controlsignal 510 is made active responsively to a trigger signal 502 beingmade active. During each exposure period e.g., period e₀, e₁, e₂ . . .pixels of image sensor array 1033 can be exposed to light focused onimage sensor array 1033 by variable focus imaging lens 1110. Terminal1000 can be operative so that after application of each exposure periode₀, e₁, e₂ . . . a readout control pulse can be applied to image sensor1032 for readout of voltages corresponding to charges accumulated onpixels of image sensor array 1033 during the preceding exposure period.A readout control signal 512 can comprise a series of readout controlpulses as indicated in the timing diagram of FIG. 9. Subsequent to areadout control pulse, image information in the form of voltages can beamplified by amplifier circuitry 1036, converted into digital format byanalog to digital converter 1037, and the converted image data can berouted by DMA unit 1070 for storage into memory 1080 which can beaddressable by CPU 1060. It is seen from the timing diagram of FIG. 9that subsequent to activation of trigger signal 502 a succession offrames can be successively stored into memory 1080 where the frames areaddressable for processing by CPU 1060. Terminal 1000 can be operativeso that memory 1080 buffers a limited and predetermined number of framessuccessfully stored therein, and discards old frames after storage of apredetermined number of succeeding frames.

Referring to further aspects of an exemplary indicia reading terminal,time plot 514 illustrates focus adjustment periods of variable focusimaging lens 1110. It has been described that variable focus imaginglens 1110 can have multiple focus positions. In one example, variablefocus imaging lens 1110 can have a shorter range focus position defininga plane of optical focus at first shorter terminal to target distance, alonger range focus position defining a plane of optical focus at adistance longer than the shorter range focus distance and can have anintermediate range focus distance being a focus distance between theshorter and the longer focus distance. In various embodiments, it can beadvantageous to vary a focus distance of variable focus imaging lens1110. In the example described with reference to the timing diagram ofFIG. 9, a focus distance of variable focus imaging lens 1110 can bevaried during a time that trigger signal 502 remains active. In anaspect illustrated with reference to FIG. 9, adjustment periods, e.g.,periods m₀, m₁, m₂ . . . are coordinated with exposure periods of imagesensor array 1033. With reference to the timing diagram of FIG. 9,adjustment periods m₀, m₁, m₂ . . . of variable focus imaging lens 1110can be timed to coincide with periods that are intermediate of exposureperiods e.g., e₀, e₁, e₂ . . . in such manner that exposure is avoidedduring times at which focus and possibly focal length characteristics ofvariable focus imaging lens 1110 are in a changing state. Frames exposedduring an adjustment period can be expected to be blurred or otherwisedisregarded. Accordingly, avoiding exposure during such periods can beadvantageous. In the example of FIG. 9, variable focus imaging lens 1110is subject to adjustment intermediate every exposure period during anactivation period of trigger signal 502. However, it is understood thata focus position and a fixed length of variable focus imaging lens 1110can remain constant through a succession of exposure periods. Variablefocus imaging lens 1110 can be selected to be of a type in which focusposition and focal length can be changed within a short time period,e.g., less than 10 ms. Where variable focus imaging lens 1110 is adeformable lens, adjustment of optical properties of the lens (e.g.focal length and therefore focal distance) can result from force beingapplied to the surface of the lens to change a concavity thereof. Wherevariable focus imaging lens 1110 is a liquid crystal lens, an adjustmentof variable focus imaging lens 1110 can result from applying anelectrical signal to variable focus imaging lens 1110 to change indicesof refraction of the lens and therefore the focal length and focaldistance of the lens.

Referring to the time plots 516 and 518 of the timing diagram of FIG. 9,CPU 1060 can subject each frame of a succession of frames to preliminaryprocessing and can subject a subset of the succession of frames todecoding processing for attempting to decode a frame of image data. Timeplot 516 illustrates times for preliminary processing of frames for CPU1060.

During preliminary processing periods p₀, p₁, p₂ . . . CPU 1060 canpreliminarily evaluate each frame of a succession of frames. Suchpreliminary processing can include e.g., detecting a quality of a framebased on average white level or a quality of a frame based on anothercriteria, incidence in sharpness of edges. Based on the result of thepreliminary processing a subset of frames of a succession of frames canbe subject to decoding processing for attempting to decode a decodableindicia represented in a frame. In the particular example of the timingdiagram of FIG. 9, CPU 1060 can subject an initial frame, frame=frame₀to decoding processing for period d₀, can switch to decoding processingof frame=frame₂ during period d₂, and can switch to decoding processingof frame=frame₄ during period d₄. In the timing diagram of FIG. 9, thesubscript indicates the frame number, e.g., exposure period e_(n-1)indicates the exposure period for frame=frame e_(n-1), processing periodp₁ indicates a preliminary processing for frame=frame₁ of a successionof frames, and decoding period, d₂, indicates a decoding processingperiod for frame=frame₂ and so on. Terminal 1000 can be operative sothat preliminary processing periods p₀, p₁, p₂ . . . are restricted fromconsuming more than a predetermined time period, e.g., more than apredetermined fraction of time. In one embodiment, preliminaryprocessing periods p₀, p₁, p₂ . . . can be restricted from consuming atime period of more than one half of a frame time, i.e., more than 8.3ms where a frame time is 16.6 ms.

Regarding binning module 10, it has been mentioned that binning module10 can bin frames of image data either in the analog domain byactivation of binning circuit 1028, or in the digital domain, e.g., byCPU 1060 by way of processing of a stored frame. Where operative to binframes in the digital domain by processing of a frame of image datastored in memory 1085, CPU 1060 can be operative to provide a binnedframe either as part of a preliminary processing of a frame during aperiod such as period p₀, p₁, p₂ . . . or as part of a decoding processsuch as during period d₀, d₁, d₂ . . . .

Referring to FIG. 1, one or more of binning module 10, windowing module20 and focus control module 30 can be controlled in a coordinated mannerfor enhanced performance of terminal 1000.

Various possible configurations of terminal 1000 are described withreference to Table A. Terminal 1000 can be operative so that any one ofthe listed configurations can be made active by operator selection of adisplayed button 1305 corresponding to the configuration. Terminal 1000can be operative to display one button 1305 corresponding to eachpossible configuration. Table A describes aspects of frames subject toprocessing during a time that trigger signal 502 remains activeaccording to each of several different configurations.

TABLE A FRAMES CONFIGURATION Frame₀ Frame₁ Frame₂ Frame₃ FRAME₄ FRAME₅ AFocus Focus Focus Focus Focus Focus Intermediate IntermediateIntermediate Intermediate Intermediate Intermediate Frame Type FrameType Frame Type Frame Type Frame Type Frame Type Normal Normal NormalNormal Normal Normal B Focus Focus Focus Focus Focus Focus IntermediateIntermediate Intermediate Intermediate Intermediate Intermediate FrameType Frame Type Frame Type Frame Type Frame Type Frame Type NormalNormal Normal Normal Normal Normal C Focus Focus Focus Focus Focus FocusIntermediate Intermediate Intermediate Intermediate Intermediate LongerFrame Type Frame Type Frame Type Frame Type Frame Type Frame Type NormalNormal Normal Normal Normal Windowed D Focus Focus Focus Focus FocusFocus Intermediate Shorter Intermediate Longer Intermediate ShorterFrame Type Frame Type Frame Type Frame Type Frame Type Frame Type NormalBinned Normal Windowed Normal Binned E Focus Focus Focus Focus FocusFocus Shorter Longer Shorter Longer Shorter Longer Frame Type Frame TypeFrame Type Frame Type Frame Type Frame Type Binned Windowed BinnedWindowed Binned Windowed F Focus Focus Focus Focus Focus Focus ShorterShorter Shorter Longer Longer Longer Frame Type Frame Type Frame TypeFrame Type Frame Type Frame Type Binned Binned Binned Windowed WindowedWindowed G Focus Focus Focus Longer Longer Longer Frame Type Frame TypeFrame Type Normal Normal Normal H Focus Focus Focus Focus Focus FocusShorter Shorter Shorter Shorter Shorter Shorter Frame Type Frame TypeFrame Type Frame Type Frame Type Frame Type Binned Binned Binned BinnedBinned Binned I Focus Focus Focus Focus Focus Focus Even Shorter ShorterIntermediate Longer Even Longer Longer Frame Type Frame Type Frame TypeFrame Type Frame Type Frame Type 4 × 4 Binned 2 × 2 Binned Normal 2592 ×512 1000 × 200 2592 × 512 Window Window Window FRAMES CONFIGURATIONFrame₆ Frame₇ Frame₈ Frame₉ . . . A Focus Focus Focus Focus . . .Intermediate Intermediate Intermediate Intermediate Frame Type FrameType Frame Type Frame Type . . . Binned Binned Binned Binned B FocusFocus Focus Focus . . . Intermediate Shorter Shorter Shorter Frame TypeFrame Type Frame Type Frame Type . . . Normal Binned Binned Binned CFocus Focus Focus Focus . . . Longer Longer Longer Longer Frame TypeFrame Type Frame Type Frame Type . . . Windowed Windowed WindowedWindowed D Focus Focus Focus Focus . . . Intermediate LongerIntermediate Shorter Frame Type Frame Type Frame Type Frame Type . . .Normal Windowed Normal Binned E Focus Focus Focus Focus Shorter LongerShorter Longer Frame Type Frame Type Frame Type Frame Type BinnedWindowed Binned Windowed F Focus Focus Focus Focus . . . Shorter ShorterShorter Longer Frame Type Frame Type Frame Type Frame Type . . . BinnedBinned Binned Windowed G H Focus Focus Focus Focus . . . Shorter ShorterShorter Shorter Frame Type Frame Type Frame Type Frame Type . . . BinnedBinned Binned Binned I Focus Focus Focus Focus Intermediate Shorter EvenShorter Shorter Frame Type Frame Type Frame Type Frame Type Normal 2 × 2Binned 4 × 4 Binned 2 × 2 Binned

When configuration A is active, terminal 1000 is operative to captureand process a succession of normal frames until a predeterminedcondition is satisfied, and then switch to processing of one or morebinned frames. The term “normal frame” in reference to Table A refers toa frame that is neither binned nor windowed. A binned frame which may beprovided by way of analog or digital binning is explained herein. Thepredetermined condition can be e.g., a time out condition (e.g.,decoding not being successful for a predetermined time from a time oftrigger signal actuation). The predetermined condition can also be e.g.,a sensed terminal to target distance or that the quality of a framesatisfies a predetermined criteria as measured by e.g., the summation ofabsolute values of the first derivative of a set of sample values atselected sampling areas of a frame. Terminal 1000 can be operative tosense a terminal to target distance utilizing an average white level ofa frame of image data. Terminal 1000 can determine that the terminal isat a relatively shorter terminal to target distance when an averagewhite level of a frame is above a predetermined threshold. The focussetting when configuration A is active does not change from frame toframe. Thus terminal 1000 can be operative in accordance withconfiguration A, even where imaging lens 1110 is not a variable focuslens but a fixed lens provided by a fixed focus imaging lens, devoid ofa capacity to vary its defined focus distance or focal length. A binnedframe can be captured at higher speeds than an unbinned frame. Hence,selection of configuration A and all configurations described hereinfeaturing binned frames can speed up decoding operations.

Regarding configuration B, configuration B is like configuration A,except that in accordance with configuration B a switch to processing ofa binned frame is timed with a certain focus setting of variable focusimaging lens 1110. In configuration B, binning of frames can beconditionally carried out in response to satisfaction of one of thepredetermined criteria as explained in connection with configuration A.However, in accordance with configuration A, a change in focus settingcan result from a predetermined criteria being satisfied. Inconfiguration B, terminal 1000 can be operative so that during anexposure period of a binned frame (which can be binned before or afterbeing subject to storage) the variable focus imaging lens 1110 is set toa shorter focus setting. Thus, in the case the target indicia is in factdisposed at the shorter focus distance, the likelihood of a successfuldecode will increase first by the sharp focus of a resulting frame andsecond by a higher SNR brought about by the binning of the frame, wherebinning is provided by averaging imaging information values associatedwith a block of pixel positions.

When in configuration C, terminal 1000 in response to a trigger signal502 being made active, can capture and process a plurality of normalframes and then switch during the activation period of signal 502 tocapture windowed frames in response to a predetermined criteria. Asnoted, the windowed frames can be captured at higher speed; henceselection of configuration C and all configurations described featuringwindowed frames speeds up decoding operations. The predeterminedcriteria can be e.g., that decoding is not successful within apredetermined time within the time period of trigger signal activationor that the terminal is at a relatively longer distance from a target(which can be indicated e.g., by an average white level of a prior framebeing below a predetermined threshold) or that the quality of a framesatisfies a predetermined criteria as measured by e.g., the summation ofabsolute values of the first derivative of a set of sample values atselected sampling areas of a frame.

In configuration D, both the focus of variable focus imaging lens 1110and the type of frame (binned, normal, windowed) switch betweensuccessive frames. The binning of frames can be synchronized to thesetting of the variable focus imaging lens at a shorter focus setting(terminal 1000 can be controlled so that during an exposure period of abinned frame the imaging lens is set to a shorter focus setting). Thecapture of normal unbinned full frames can be synchronized to anintermediate focus setting (terminal 1000 can be controlled so thatduring an exposure period of a normal frame, the variable focus imaginglens is set to an intermediate focus setting). The capture of windowedframes can be synchronized with the setting of a variable focus imaginglens 1110 at a longer range focus setting (terminal 1000 can becontrolled so that during an exposure period of a windowed frame theimage lens is set to a longer focus setting).

Referring to operation in accordance with configuration E, operation inaccordance with configuration E active is like operation withconfiguration D active except the frame characteristics switch betweenbinned and windowed frames with no normal (unbinned, unwindowed) framesbeing captured. Accordingly, each frame captured with trigger signal 502and configuration E active can be captured at a faster frame timerelative to that of an unbinned frame and can have reduced memoryoverhead bandwidth relative to that of a normal frame.

In the embodiment of configurations D and E, the switching betweenbinned, normal (configuration D), and windowed frames, each synchronizedwith a setting of variable focus imaging lens 1110 at a certain lenssetting for each frame type, can be made according to an open loopoperation, where the switching is made without the switching beingconditional on a predetermined condition being satisfied (e.g., aterminal to target distance, an elapsed decode type). However, in avariation of configurations D and E, terminal 1000 is operative so thatthe switching between frame types (each synchronized with a specificlens setting) is conditional on a predetermined condition beingsatisfied (e.g., an elapsed decode time threshold being satisfied or apredetermined terminal to target distance being satisfied).

Referring to configuration F, the operation of terminal 1000 inaccordance with configuration F is similar to its operation inaccordance with configuration E, except that the focus setting and frametype do not switch for each successive frame. Instead, the focus settingand frame type (binned, windowed) remain constant for a predeterminednumber (3 in the described example) and then switch to a new focussetting and frame time. In configuration F, like configuration E, eachframe is either a binned frame or a windowed frame. Accordingly, eachframe captured with configuration F active can be captured with a fasterframe time than a frame time of an unbinned full frame. The windowedframes in the examples of configurations C, D, E, and F can be windowedframes having image data corresponding to (representing light incidentat) a continuous group of pixels of sufficient size so that image dataof the windowed frames can represent a complete decoded indicia (butsince decoding as will be described can be accomplished by associatingcode words for certain symbols given, need not represent a completeindicia for decoding to be successful). In one example, the windowedframes can be image data representing light incident at a continuous2592×512 group of pixels centered at a center of image sensor 1032 whenimage sensor 1032 has 2592×1944 total pixels.

Regarding configurations G and H, configurations G and H can beadvantageous to activate in many use cases including the use case thatimage sensor array 1033 has disposed thereon a color filter such as aBayer pattern filter. It has been mentioned that activation of binningmodule 10 converts a color frame generated with use of a color filterinto a monochrome frame, which, though having a lower resolution,features an improved SNR relative to that of an unbinned frame withoutdiscarding of image information. Activation of configuration G in TableA can be regarded as activation of a picture taking mode of operation.When operating in a picture taking mode of operation, terminal 1000 inresponse to activation of trigger signal 502 can capture and can outputa color frame of image data. For output of a color frame of image data,terminal 1000 can write a color frame to display 1304 and/or write theframe to non-volatile memory 1084. For output of a color frame, terminal1000 alternatively or in addition to can transmit the frame via I/Ointerface 1604, 1608 to an external CPU-based terminal (e.g., a remoteserver, a local personal computer).

In the example of configuration G, terminal 1000, in response toactivation of a trigger signal 502 with configuration G active cancapture a limited predetermined number of frames (three in theparticular example). CPU 1060 can average the three frames for noisereduction prior to outputting the resulting noise reduced frame as theframe output during operation in a picture taking mode. Decodingprocessing as described in connection with periods as described inconnection with the timing diagram of FIG. 9 can be avoided (indiciadecoding module 40 disabled) when terminal 1000 operates in a picturetaking mode. Indicia decoding module 40 can also be enabled withconfiguration G active, and can be enabled with all other configurationsof Table A so that a subset of frames captured during an activationperiod are subject to a decode attempt.

As indicated in Table A, terminal 1000, when a picture taking mode isactive, can set a focus setting of variable focus imaging lens 1110 to alonger range focus setting (such that the imaging lens is set to thelonger focus setting during the exposure period for each frame) giventhe expectancy that most pictures taken with the mode active will betaken at long range.

Referring now to configuration H, terminal 1000 with configuration Hactive, can bin (prior to or after a filter capture) each captured framecaptured when trigger signal 502 is active. Thus, each frame captured(capture complete by storage into memory 1085) can be converted from acolor frame to a monochrome frame such that it is in a form that isprocessable with use of a known decoding algorithm adapted for use witha monochrome frame. During the exposure period for each binned frame,imaging lens 1110 can be set to a shorter focus setting so that thelikelihood of successfully decoding a decodable indicia by processing aframe captured at short range is increased.

As is indicated by configuration I, the block size of a block of pixelpositions subject to binning can be a variable block size. Further,terminal 1000 can be operative so that the binning block size issynchronized with and varies with the lens setting of variable focusimaging lens 1110. In the example of configuration I, terminal 1000 canbe capable of 4×4 block binning and can have an “even shorter” focusposition relatively shorter than the focus position referred to as“shorter.” In such an embodiment, exposure of a 4×4 block frame can besynchronized with the even shorter focus distance setting in the mannerof synchronization described herein. Such an adjustment of the focusposition can follow the pattern summarized in Table A. Also inaccordance with the configuration I, terminal 1000 can be capable ofwindowing at variable window sizes and can have an “even longer” focusposition that is relatively longer than the focus position designated as“longer.” Terminal 1000 in the specific window can be capable of captureof a 2952×512 windowed frame corresponding to continuous 2952×512 groupof pixels at a center of array 1033 as well as a smaller 1000×200windowed frame corresponding to continuous 2952×512 group of pixels at acenter of array 1033. According to the frame capture and image focusadjustment pattern, terminal 1000 can adjust a frame setting to “evenlonger” after exposure at a “longer” focus position and can expose asmaller windowed frame when the lens setting is the “even longer” focussetting, the exposure period and lens setting being synchronized in themanner described herein. The variable binning size and variablewindowing size shown in configuration I can be implemented as part of atrial and error image capture scheme wherein terminal 1000 captures aplurality of frames for processing according to an open loop operationwithout detecting a sensed terminal to target distance or any otherpredetermined criteria. A variable bin size and/or a variable windowingsize scheme can also be implemented as part of a detected predeterminedcriteria scheme as explained in connection with configurations B and Cwherein terminal 1000 can activate binning module 10 (configuration B)or windowing module 20 (configuration C) in response to a detectedcriteria (e.g., a terminal to target distance, a decode time). It wasalso described with reference to various configurations that a focussetting can be coordinated with activation of binning module 10 andwindowing module 20 (e.g., activation of binning module 10 can besynchronized with a setting of imaging lens 1110 at a shorter focussetting, and activation of windowing module 20 can be synchronized witha setting of imaging lens 1110 at a longer focus setting). It will beseen that terminal 1000 can be adapted to vary a bin size responsivelyto a detected terminal to target distance and to associate a certain binsize for a certain terminal to target distance to a synchronized certainfocus setting. Terminal 1000 can also vary a window size responsive to adetected terminal to target distance and to associate a certain windowsize for a certain terminal to target distance to a synchronized certainfocus setting. Also, terminal 1000 can be adapted so that no matter themethod for detecting the bin size or window size, the established binsize or window size can be associated with a synchronized certain focussetting. Also, terminal 1000 can be adapted so that without anydetecting method for detecting a sensed condition the terminal accordingto an open loop operation, can establish a bin size or window size to beassociated with a synchronized certain focus setting.

Referring now to processes that can be carried out by indicia decodingmodule 40 during, e.g., periods d₀, d₂, d_(n-4) of FIG. 9, CPU 1060,appropriately programmed can carry out a decoding process for attemptingto decode a frame of image data. For attempting to decode a frame ofimage data, CPU 1060 can sample image data of a captured frame of imagedata along a sampling path, e.g., at a center of a frame, or acoordinate location determined to include a decodable indiciarepresentation. In one example, a sampling path selected for executing adecode attempt can be a sampling path which for a previous frame wasdetermined to intersect a decodable indicia representation. Next, CPU1060 can perform a second derivative edge detection to detect edges.After completing edge detection, CPU 1060 can determine data indicatingwidths between edges. CPU 1060 can then search for start/stop characterelement sequences and if found, derive element sequence characters,character by character by comparing with a character set table. Forcertain symbologies, CPU 1060 can also perform a checksum computation.If CPU 1060 successfully determines all characters between a start/stopcharacter sequence and successfully calculates a checksum (ifapplicable), CPU 1060 can output a decoded message.

Where a decodable indicia representation is a 2D bar code symbology, adecode attempt can comprise the steps of locating a finder pattern usinga feature detection algorithm, locating scan lines intersecting thefinder pattern according to a predetermined relationship with the finderpattern, determining a pattern of dark and light cells along the scanlines, and converting each light pattern into a character or characterstring via table lookup. In one example, terminal 1000 can be adapted sothat CPU 1060 subjects each frame captured during a time that a triggersignal remains active to a decode attempt (e.g., frame=frame0, frame1,frame2 . . . in any of the configurations described with reference toTable A). In an alternative example, as has been described herein,terminal 1000 can be adapted so that CPU 1060 subjects only a subset offrames to a decode attempt, and selects frames for subjecting todecoding according to a predetermined criteria.

It should be noted that when switching to decoding a new frame (i.e.,the switch from frame=frame₀ during period d₀ to frame=frame₂ duringperiod d₂) terminal 1000 may not discard the results of decoding theprevious frame. For example, in some instances, a decodable indiciasubject to decoding can be a bar code of a symbology type that can bedecodable to output code words. Code words of a bar code symbol are notcomplete decoded messages of a bar code symbol but can be combined withother code words of a bar code symbol to provide a complete decodedmessage. A decoded code word of a bar code symbol may be regarded as apartially decoded message. Symbologies which may be decoded to providecode words representing a partial decoded message of a bar code symbolinclude PDF 417, UPC, Datamatrix, QR code, and Aztec, etc. Terminal 1000can be operative to accumulate partially decoded messages determined byprocessing a set of subject frames until a decoded message for a symbolis determined. For decoding bar code decodable indicia of certainsymbologies, CPU 1060 can be adapted to combine partial decoded outresults determined from two or more different frames. A partial decoderesult provided by decoding a frame of image data can take the form of aset of code words. CPU 1060 can be adapted to determine a first set ofcode words by processing a certain frame of a set of frames while atrigger signal 502 is active and to combine the first set of code wordswith a second set of code words determined by processing of a subsequentframe while the trigger signal 502 remains active. In one embodiment,CPU 1060 can be adapted so that CPU 1060 can process a certain frame todetermine a first set of code words, a subsequent frame to provide asecond set of code words, and possibly M further subsequent frames toprovide a third set of code words. CPU 1060 can further be adapted tocombine the first, second, and possible M additional sets of code wordsto provide a decoded message. For example, with reference to the timingdiagram of FIG. 9, CPU 1060 may process frame=frame₀ to determine afirst set of code words and then process frame=frame₂ to determine asecond set of code words and then combine the code words to provide adecoded message output after the expiration of period d_(n-4).

A small sample of systems methods and apparatus that are describedherein is as follows:

-   A1. An indicia reading terminal comprising:

an image sensor integrated circuit having a two dimensional image sensorarray, said two dimensional image sensor array including a plurality ofpixels, said indicia reading terminal including a binning module forapplying a function using image information values representative oflight incident at a plurality of pixels of said image sensor array, saidindicia reading terminal further including a windowing module for use inselectively addressing a subset of pixels of said image sensor array forread out of a windowed frame;

an imaging lens for use in focusing an image of a target decodableindicia onto said two dimensional image sensor array;

a hand held housing encapsulating said two dimensional image sensorarray, said indicia reading terminal being operative for manualactivation of a trigger signal by an operator;

wherein said hand held indicia reading terminal is operative so that fora time that said trigger signal remains active, said hand held indiciareading terminal can process a succession of frames, said succession offrames including a binned frame, said succession of frames furtherincluding a windowed frame, the windowed frame having image datarepresenting light incident at a group of pixels of said image sensorarray, the group of pixels comprising less than 50% of a total number ofpixels of said image sensor array, the windowed frame representingindicia within a defined area of a target substrate that is relativelysmaller than a defined area within which indicia would be represented bya frame representing light incident on each pixel of said image sensorarray;

wherein said hand held indicia reading terminal is operative to processa frame of said succession of frames for attempting to decode fordecodable indicia.

-   A2. The indicia reading terminal of claim A1, wherein said imaging    lens is a variable focus imaging lens capable of defining a    plurality of best focus distances.-   A3. The indicia reading terminal of claim A1, wherein said imaging    lens is a variable focus imaging lens capable of defining a    plurality of best focus distances, and wherein said indicia reading    terminal is operative so that said variable focus imaging lens is    moved between a plurality of best focus distance settings ranging    between a shorter range and longer range during said time that said    trigger signal remains active, said indicia reading terminal being    operative so that said variable focus imaging lens is controlled to    be in said shorter range best focus distance setting during an    exposure period for said binned frame.-   A4. The indicia reading terminal of claim A1, wherein said imaging    lens is a variable focus imaging lens capable of defining a    plurality of best focus distances, and wherein said indicia reading    terminal is operative so that said variable focus imaging lens is    moved between a plurality of best focus distance settings ranging    between a shorter range and a longer range during said time that    said trigger signal remains active, said indicia reading terminal    being operative so that said variable focus imaging lens is    controlled to be in said longer range best focus distance setting    during an exposure period for said windowed frame.-   A5. The indicia reading terminal of claim A1, wherein said binning    module includes an analog binning circuit incorporated in said image    sensor integrated circuit for summing charges that have accumulated    on a block of said plurality of pixels.-   A6. The indicia reading terminal of claim A1, wherein said binning    module averages image information values that are associated with a    block of pixel positions.-   A7. The indicia reading terminal of claim A1, wherein said binning    module includes a CPU that sums multibit pixel values that are    associated with a block of pixel positions.-   A8. The indicia reading terminal of claim A1, wherein said imaging    lens is one of a deformable lens or a non-deformable fluid lens.-   A9. The indicia reading terminal of claim A1, wherein said indicia    reading terminal is operative to capture a full unbinned frame, the    full unbinned frame having a certain frame time, where a frame time    of said windowed frame is less than said certain frame time.-   A10. The indicia reading terminal of claim A1, wherein said indicia    reading terminal is operative so that said terminal captures said    windowed frame conditionally on satisfaction of a predetermined    criteria.-   A11. The indicia reading terminal of claim A1, wherein said group of    pixels is a continuous group of pixels centered at a center of said    image sensor array.-   B1. An indicia reading terminal comprising:

an image sensor integrated circuit having a two dimensional image sensorarray, said two dimensional image sensor array including a plurality ofpixels, said indicia reading terminal including a binning moduleapplying a function using image information values representative oflight incident at a plurality of pixels of said image sensor array;

an imaging lens for use in focusing an image of a target decodableindicia onto said two dimensional image sensor array;

a hand held housing encapsulating said two dimensional image sensorarray, said indicia reading terminal being operative for manualactivation of a trigger signal by an operator;

wherein said hand held indicia reading terminal is operative so that fora time that said trigger signal remains active, said hand held indiciareading terminal can process a succession of frames, said succession offrames including a first binned frame and a second binned frame;

wherein said hand held indicia reading terminal is operative to processa frame of said succession of frames for attempting to decode fordecodable indicia; and

wherein said first binned frame has a bin size larger than a bin size ofsaid second binned frame, and wherein said imaging lens is a variablefocus imaging lens capable of defining a plurality of best focusdistances, and wherein said indicia reading terminal is operative sothat said variable focus imaging lens is moved between first and secondbest focus distance settings during said time that said trigger signalremains active, said first best focus distance being relatively shorterthan said second best focus distance, said indicia reading terminalfurther being operative so that said variable focus imaging lens iscontrolled to be at said first best focus distance during an exposureperiod for said first binned frame, said indicia reading terminalfurther being operative so that said variable focus imaging lens iscontrolled to be at said second best focus distance during an exposureperiod for said second binned frame.

-   B2. The indicia reading terminal of claim B1, wherein said imaging    lens is a variable focus imaging lens capable of defining a    plurality of best focus distances.-   B3. The indicia reading terminal of claim B1, including a color    pattern filter disposed over said image sensor array, said indicia    reading terminal being operative so that said binning module can be    activated to convert color image information to monochrome image    information.-   B4. The indicia reading terminal of claim B1, wherein said    succession of frames that can be processed for said time that said    trigger signal remains active includes an unbinned frame.-   B5. The indicia reading terminal of claim B1, wherein said    succession of frames includes a windowed frame.-   B6. The indicia reading terminal of claim B1, wherein said    succession of frames includes a first binned frame and a second    binned frame, said first binned frame having a bin size larger than    a bin size of said second binned frame.-   B7. The indicia reading terminal of claim B1, wherein said terminal    is operative so that said terminal processes said second binned    frame conditionally on satisfaction of a predetermined criteria.-   B8. The indicia reading terminal of claim B1, wherein said imaging    lens is one of a deformable lens or a non-deformable fluid lens.-   C1. An indicia reading terminal comprising:

an image sensor integrated circuit having a two dimensional image sensorarray, said two dimensional image sensor array including a plurality ofpixels, said indicia reading terminal including a windowing module foruse in selectively addressing a subset of pixels of said image sensorarray for read out of a windowed frame having image data;

an imaging lens for use in focusing an image of a target decodableindicia onto said image sensor array;

a hand held housing encapsulating said two dimensional image sensorarray, said indicia reading terminal being operative for manualactivation of a trigger signal by an operator;

wherein said indicia reading terminal is operative for capture of asuccession of frames during a time that said trigger signal remainsactive, wherein said succession of frames includes a first frame and asecond windowed frame, said first frame representing light incident on alarger number of pixels of said image sensor array than said secondwindowed frame, wherein said second windowed frame represents lightincident at a group of pixels comprising less than 50% of a total numberof pixels of said image sensor array, wherein said imaging lens is avariable focus imaging lens capable of defining a plurality of bestfocus distances, and wherein said indicia reading terminal is operativeso that said variable focus imaging lens is moved between first andsecond best focus distance settings during said time that said triggersignal remains active, said first best focus distance being relativelyshorter than said second best focus distance, said indicia readingterminal further being operative so that said variable focus imaginglens is controlled to be at said first best focus distance during anexposure period for said first frame, said indicia reading terminalfurther being operative so that said variable focus imaging lens iscontrolled to be at said second best focus distance during an exposureperiod for said second windowed frame; and

wherein said hand held indicia reading terminal is operative to processa frame of said succession of frames for attempting to decode fordecodable indicia.

-   C2. The indicia reading terminal of claim C1, wherein said imaging    lens is one of a deformable lens or a non-deformable fluid lens.-   C3. The indicia reading terminal of claim C1, wherein said first    frame is a windowed frame representing light incident at a    continuous group of pixels of said image sensor array, where said    continuous group of pixels comprises less than 80% of a total number    of pixels of said image sensor array.-   C4. The indicia reading terminal of claim C1, wherein said terminal    is operative so that said terminal captures said second windowed    frame conditionally on the satisfaction of a predetermined criteria.-   D1. An indicia reading terminal comprising:

an image sensor integrated circuit having a two dimensional image sensorarray, said two dimensional image sensor array including a plurality ofpixels and a color pattern filter disposed over said two dimensionalimage sensor array, said indicia reading terminal including a binningmodule for summing signal values representative of light incident at ablock of said plurality of pixels of said image sensor array;

an imaging lens for use in focusing an image of a target decodableindicia onto said image sensor array;

a hand held housing encapsulating said two dimensional image sensorarray, said indicia reading terminal being operative for manualactivation of a trigger signal by an operator;

wherein said hand held indicia reading terminal is operative in apicture taking mode and an indicia decoding mode, said indicia readingterminal further being operative so that when said terminal is operatedfor capture of a succession of frames with said picture taking modeactive said binning module is not enabled so that said succession offrames captured with said picture taking mode active include color imagedata, said indicia reading terminal further being operative so that whensaid terminal is operated to process a succession of the frames withsaid indicia decoding mode active said binning module is enabled so thatsaid succession of frames processed with said indicia decoding modeactive includes a binned frame including monochrome image data forsubjecting to an indicia decode attempt.

-   D2. The indicia reading terminal of claim D1, wherein said imaging    lens is one of a deformable lens or a non-deformable fluid lens.

While the present invention has been described with reference to anumber of specific embodiments, it will be understood that the truespirit and scope of the invention should be determined only with respectto claims that can be supported by the present specification. Further,while in numerous cases herein wherein systems and apparatuses andmethods are described as having a certain number of elements it will beunderstood that such systems, apparatuses and methods can be practicedwith fewer than the mentioned certain number of elements.

1. An indicia reading terminal comprising: an image sensor integrated circuit having a two dimensional image sensor array, said two dimensional image sensor array including a plurality of pixels, said indicia reading terminal including a binning module for applying a function using image information values representative of light incident at a plurality of pixels of said image sensor array, said indicia reading terminal further including a windowing module for use in selectively addressing a subset of pixels of said image sensor array for read out of a windowed frame; an imaging lens for use in focusing an image of a target decodable indicia onto said two dimensional image sensor array; a hand held housing encapsulating said two dimensional image sensor array, said indicia reading terminal being operative for manual activation of a trigger signal by an operator; wherein said hand held indicia reading terminal is operative so that for a time that said trigger signal remains active, said hand held indicia reading terminal can process a succession of frames, said succession of frames including a binned frame, said succession of frames further including a windowed frame, the windowed frame having image data representing light incident at a group of pixels of said image sensor array, the group of pixels comprising less than 50% of a total number of pixels of said image sensor array, the windowed frame representing indicia within a defined area of a target substrate that is relatively smaller than a defined area within which indicia would be represented by a frame representing light incident on each pixel of said image sensor array; wherein said hand held indicia reading terminal is operative to process a frame of said succession of frames for attempting to decode for decodable indicia.
 2. The indicia reading terminal of claim 1, wherein said imaging lens is a variable focus imaging lens capable of defining a plurality of best focus distances.
 3. The indicia reading terminal of claim 1, wherein said imaging lens is a variable focus imaging lens capable of defining a plurality of best focus distances, and wherein said indicia reading terminal is operative so that said variable focus imaging lens is moved between a plurality of best focus distance settings ranging between a shorter range and longer range during said time that said trigger signal remains active, said indicia reading terminal being operative so that said variable focus imaging lens is controlled to be in said shorter range best focus distance setting during an exposure period for said binned frame.
 4. The indicia reading terminal of claim 1, wherein said imaging lens is a variable focus imaging lens capable of defining a plurality of best focus distances, and wherein said indicia reading terminal is operative so that said variable focus imaging lens is moved between a plurality of best focus distance settings ranging between a shorter range and a longer range during said time that said trigger signal remains active, said indicia reading terminal being operative so that said variable focus imaging lens is controlled to be in said longer range best focus distance setting during an exposure period for said windowed frame.
 5. The indicia reading terminal of claim 1, wherein said binning module includes an analog binning circuit incorporated in said image sensor integrated circuit for summing charges that have accumulated on a block of said plurality of pixels.
 6. The indicia reading terminal of claim 1, wherein said binning module averages image information values that are associated with a block of pixel positions.
 7. The indicia reading terminal of claim 1, wherein said binning module includes a CPU that sums multibit pixel values that are associated with a block of pixel positions.
 8. The indicia reading terminal of claim 1, wherein said imaging lens is one of a deformable lens or a non-deformable fluid lens.
 9. The indicia reading terminal of claim 1, wherein said indicia reading terminal is operative to capture a full unbinned frame, the full unbinned frame having a certain frame time, where a frame time of said windowed frame is less than said certain frame time.
 10. The indicia reading terminal of claim 1, wherein said indicia reading terminal is operative so that said terminal captures said windowed frame conditionally on satisfaction of a predetermined criteria.
 11. The indicia reading terminal of claim 1, wherein said group of pixels is a continuous group of pixels centered at a center of said image sensor array.
 12. An indicia reading terminal comprising: an image sensor integrated circuit having a two dimensional image sensor array, said two dimensional image sensor array including a plurality of pixels, said indicia reading terminal including a binning module applying a function using image information values representative of light incident at a plurality of pixels of said image sensor array; an imaging lens for use in focusing an image of a target decodable indicia onto said two dimensional image sensor array; a hand held housing encapsulating said two dimensional image sensor array, said indicia reading terminal being operative for manual activation of a trigger signal by an operator; wherein said hand held indicia reading terminal is operative so that for a time that said trigger signal remains active, said hand held indicia reading terminal can process a succession of frames, said succession of frames including a first binned frame and a second binned frame; wherein said hand held indicia reading terminal is operative to process a frame of said succession of frames for attempting to decode for decodable indicia; and wherein said first binned frame has a bin size larger than a bin size of said second binned frame, and wherein said imaging lens is a variable focus imaging lens capable of defining a plurality of best focus distances, and wherein said indicia reading terminal is operative so that said variable focus imaging lens is moved between first and second best focus distance settings during said time that said trigger signal remains active, said first best focus distance being relatively shorter than said second best focus distance, said indicia reading terminal further being operative so that said variable focus imaging lens is controlled to be at said first best focus distance during an exposure period for said first binned frame, said indicia reading terminal further being operative so that said variable focus imaging lens is controlled to be at said second best focus distance during an exposure period for said second binned frame.
 13. The indicia reading terminal of claim 12, wherein said imaging lens is a variable focus imaging lens capable of defining a plurality of best focus distances.
 14. The indicia reading terminal of claim 12, including a color pattern filter disposed over said image sensor array, said indicia reading terminal being operative so that said binning module can be activated to convert color image information to monochrome image information.
 15. The indicia reading terminal of claim 12, wherein said succession of frames that can be processed for said time that said trigger signal remains active includes an unbinned frame.
 16. The indicia reading terminal of claim 12, wherein said succession of frames includes a windowed frame.
 17. The indicia reading terminal of claim 12, wherein said succession of frames includes a first binned frame and a second binned frame, said first binned frame having a bin size larger than a bin size of said second binned frame.
 18. The indicia reading terminal of claim 12, wherein said terminal is operative so that said terminal processes said second binned frame conditionally on satisfaction of a predetermined criteria.
 19. The indicia reading terminal of claim 12, wherein said imaging lens is one of a deformable lens or a non-deformable fluid lens.
 20. An indicia reading terminal comprising: an image sensor integrated circuit having a two dimensional image sensor array, said two dimensional image sensor array including a plurality of pixels, said indicia reading terminal including a windowing module for use in selectively addressing a subset of pixels of said image sensor array for read out of a windowed frame having image data; an imaging lens for use in focusing an image of a target decodable indicia onto said image sensor array; a hand held housing encapsulating said two dimensional image sensor array, said indicia reading terminal being operative for manual activation of a trigger signal by an operator; wherein said indicia reading terminal is operative for capture of a succession of frames during a time that said trigger signal remains active, wherein said succession of frames includes a first frame and a second windowed frame, said first frame representing light incident on a larger number of pixels of said image sensor array than said second windowed frame, wherein said second windowed frame represents light incident at a group of pixels comprising less than 50% of a total number of pixels of said image sensor array, wherein said imaging lens is a variable focus imaging lens capable of defining a plurality of best focus distances, and wherein said indicia reading terminal is operative so that said variable focus imaging lens is moved between first and second best focus distance settings during said time that said trigger signal remains active, said first best focus distance being relatively shorter than said second best focus distance, said indicia reading terminal further being operative so that said variable focus imaging lens is controlled to be at said first best focus distance during an exposure period for said first frame, said indicia reading terminal further being operative so that said variable focus imaging lens is controlled to be at said second best focus distance during an exposure period for said second windowed frame; and wherein said hand held indicia reading terminal is operative to process a frame of said succession of frames for attempting to decode for decodable indicia.
 21. The indicia reading terminal of claim 20, wherein said imaging lens is one of a deformable lens or a non-deformable fluid lens.
 22. The indicia reading terminal of claim 20, wherein said first frame is a windowed frame representing light incident at a continuous group of pixels of said image sensor array, where said continuous group of pixels comprises less than 80% of a total number of pixels of said image sensor array.
 23. The indicia reading terminal of claim 20, wherein said terminal is operative so that said terminal captures said second windowed frame conditionally on the satisfaction of a predetermined criteria.
 24. An indicia reading terminal comprising: an image sensor integrated circuit having a two dimensional image sensor array, said two dimensional image sensor array including a plurality of pixels and a color pattern filter disposed over said two dimensional image sensor array, said indicia reading terminal including a binning module for summing signal values representative of light incident at a block of said plurality of pixels of said image sensor array; an imaging lens for use in focusing an image of a target decodable indicia onto said image sensor array; a hand held housing encapsulating said two dimensional image sensor array, said indicia reading terminal being operative for manual activation of a trigger signal by an operator; wherein said hand held indicia reading terminal is operative in a picture taking mode and an indicia decoding mode, said indicia reading terminal further being operative so that when said terminal is operated for capture of a succession of frames with said picture taking mode active said binning module is not enabled so that said succession of frames captured with said picture taking mode active include color image data, said indicia reading terminal further being operative so that when said terminal is operated to process a succession of the frames with said indicia decoding mode active said binning module is enabled so that said succession of frames processed with said indicia decoding mode active includes a binned frame including monochrome image data for subjecting to an indicia decode attempt.
 25. The indicia reading terminal of claim 24, wherein said imaging lens is one of a deformable lens or a non-deformable fluid lens. 